Telegraph apparatus



1 y A. E. THOMPSON mm. fim

TELEGRAPH APPARATUS Filed Aug. 20, 1943 s Sheets- Sheet 1 jwfiy 16, mm A. E- THOMPSON El'AL v 9 I TELEGRAPH APPARATUS Filed Aug. 20,1943- s Sheets-Shet. 2

July 16, 1946.

A. E. THOMPSON ETAL I TELEGRAPH APPARATUS Filed Aug. 20, 1945 3 SheetsSheet 5 Patented July 16, 1946 TELEGRAPH APPARATUS Alfred Edward Thompson and Reginald Dennis Salmon, Croydon, England, assignors to Creed and Company LimitedCroydon, England Application August 20, 1943, Serial No. 499,310 In'Great Britain August 21, 1942 19 Claims.

This invention relates to keyboard transmitters for Morse signals.

Manual Morse working has many important advantages, particularly in wireless communication, but unfortunately it involves operators with a high degree of telegraphic skill. Moreover, in manual working it is notpossible to obtain strict operating uniformity, either as regards .signal formation or speed oftransmission. An operator cannot transmit with machine precision and it is also difficult for him to maintain a.v .pre-determined speed, particularly if this is below the maximum speed at whichhe is capable of working.

It is the object of the present invention. to provide a simple and ruggedinstrument, adapted for operation at the normal speeds of present manual working whichonly requires .the operator to possess moderate typing skill.

Morse keyboard transmitters have previously been proposed but it is believed that not one of them was a really practicable instrument orwas adapted for full keyboardlocking as is usual on keyboard transmitters for. equal letter code signals.

lhe keyboard transmitter according. to the present invention may work with a receiver which prints the representations of the dots and dashes on a tape. Knowledge of the Morse alphabet is desirable, of course, for translating. the signals as printed on the tape, butthe degree of knowledge necessary is not great. .Anyonecan read the tape by referring to a list of Morse characters andaiter only a few hours practice evenithis aid is found to be not required.

One feature of the present. invention consists in a keyboard operated Morse transmitter comprising means operable on actuation of a key to analyse the Morse signals representative of. said key into elements and to cause the transmission of said elements in correct combinational sequence and means operable upon the final element having been transmitted to return the mechanism rapidly to a position ready to transmit another signal.

Another feature of the invention consists in a keyboard operated Morse transmitter comprising combination bars, means actuated by the operation of a key to set the combination bars into positions characteristic of the respective elements of the Morse signal representative of said key and to cause the said elements to be transmitted in correct sequence. Preferably the combination bars are provided in number equal to :the maximum number of elements, less one, in any signal and means is provided to set each bar not required for the elements of a signal into position representing the last element of a signal which is invariably a space.

Yet-another feature of the invention is a keyboard operated Morse transmitter comprising three-separate means for transmitting the three different elements of a Morse signal and means operable on the actuation of a key for actuating said separate means in the correct combinational sequence to transmit the Morse signal'representative of said key. 7

In the preferred embodiment of the invention three cams are independently driven to transmit different elements of a Morse signal and are released for rotation inthe correct combinational sequence on actuation of a key.

A further feature of the invention is a keyboard operated Morse transmitter comprising means for locking the keyboard'duringthe transmission of asignal representative of a key that has been actuated and means operative in the case of a signal less than the maximum length for unlocking the keyboard on the conclusion of a-short interval following the transmission of a signal and before the lapse of the time necessary to transmit a signal .of maximum length.

' TheMorse land line code uses two line condi tions only, viz. marking and spacing. A dot is constituted by a mark of onetime unit followed by a space of one time unit, a dash is constituted by a mark of three time units followed by a space of one time unit, whilst a letter space is constituted by a space of two time units.

ing a signalcompletes a word space, andthus a space of two units-duration can beregarded as a separate character.

It will be understood that, because the characters of the Morse code vary in time required for transmission, the rate at which the-keys of the keyboard can be depressed will vary in like manner. It follows, therefore, that if the machine is adjusted so that the signalling rate is equal to,-forexample, 20 words per minute, the

rateatwhich the keys may be depressed will vary from about 10 words per minute to about 80 words per minute, according to whether they correspond to long or short signals. The highest rate at which the keys must be operated corresponds to the space key and the next highest rate corresponds to the letter E. If the time available for the depression of these two keys is increased, the maximum rate at which the keys must be depressed will be reduced to about 30 words per minute. A variation in rate of the operation of the keys from 10 to 30 Words per minute for the signal speed of 20 words per minute does not impose any strain upon the operator.

For this purpose the keys corresponding to characters represented by the shortest Morse signals, namely those for the letter E and the word space are preferably arranged so that the fingers of the operator can actuate them whilst a signal corresponding to a previously actuated key is being transmitted and a separate mechanism is preferably provided for actuation by these keys.

This separate mechanism is preferably so arranged that either of these two keys can be actuated whilst the main mechanism is transmitting, the mechanism being arranged to store the signal so that either of these two signals is not transmitted until the main mechanism has finished transmitting. If one of the two keys mentioned is actuated, however, the whole keyboard is locked until the corresponding signal has been transmitted.

The transmitter according to the invention may be combined with a Morse signal recorder driven by the same motor as the transmitter. A send-receive switch is then provided and is combined with a lever which starts or stops the tape.

The nature of the invention will be better understood from the following description of a preferred embodiment thereof taken in conjunction with the accompanying drawings in which:

Figs. 1 and 2 are an exploded perspective view of one embodiment of the invention; and

Figs. 3 and 4 are an exploded perspective view of a supplementary transmitter for the shortest signals adapted to form part of the transmitter of Figs. 1 and 2 showing how the supplementary transmitter is positioned and inter-related with that shown in Figs. 1 and 2, and how the transmitter of Figs. 1 and 2 is modified for this inter-relation.

Referring to the drawings, an outline description of the construction and operation of the Morse keyboard transmitter shown in Figs. 1 and 2 will first be given, and then a more detailed description. The machine shown has six combination bars, one only of which is shown. The depression of a key bar 6 sets all six combination bars, the result being to move a portion of each such as either to left or right or to leave it in the position shown, and also to move a trip bar it? to the left. To the portion 5 of a combination bar is fixed an extension 38. These extensions co-operate with sliding bars 39a, 39b, 39c, SM, 39c, 39 of which only the last mentioned is fully shown, the others being shown broken away. Each sliding bar is accordingly positioned under one or other of three frame members 55, 66, 41. The movement of the trip bar it allows of a shaft 22 being rotated in step-by-step manner. Cams 42a 42 act in turn during the respective steps of movement on sliding bars 39a 39] and raise these bars into engagement with one of the frame members 35, 46, 47 If frame member 45 is moved by a d sliding bar, it releases a sleeve 59 for rotation and a cam 54 thereon acts to operate contacts 61 to send a dot. If frame member 46 is moved, it releases a sleeve 6! for rotation and a cam 63 thereon operates contacts 67 to send a dash. In either case shaft 22 is then allowed to rotate, after the required signal element has been transmitted, for a further step, and the next signal-element i transmitted. When frame member 41 is raised, indicating that a space element is to be sent, a sleeve 76 is released for rotation and after the space element has been sent releases the shaft 22 for rotation into initial position, in which it is arrested. During rotation of shaft 22, a frame member 3i locks the keyboard, but is withdrawn from looking position when shaft 22 reaches its home position.

The apparatus is driven by a motor 25 which can also drive a tape feeding mechanism for a recorder, which prints dots and dashes corresponding to received signals on a tape. A sendreceive switch is provided with a member 92 which in one position of said switch causes motor 25 to drive the recorder.

Preferably the keys for the letter E and the letter space signal do not act on the combination bars but are, as shown in Figs. ,3 and 4, associated with storage mechanism whereby these keys may be actuated during the time that the preceding signal is being transmitted.

The construction and operation of the apparatus will now be described in detail. Referring now to Figs. 1 and 2, all the combination bars are similar to the one shown. This consists of two members If and 2f pivoted at their ends to three armed levers 3] and 4]. The third arms of the three armed levers 3 and 4] are connected together by a link 5 If the member If is pushed downwards the member 2] must rise, the levers 31 and. 4f acting as a see-saw or balance, and link 5] is moved to the right. If member 2 is pushed downwards the member If must rise and link 5] is moved to the left.

A set of key bars such as 53 is arranged in well known manner over the combination bars, and the members If and, 2f and the corresponding members of all the other combination bars are cut with notches of various depths in relation to the key bars, so that the links such as 5 are moved in accordance with the elements of the Morse signal representative of the particular key actuated.

I In the form shown the key bars 6 are pivoted at their ends remote from the keys and are depressed against the pressure of individual springs (not shown) and the upper surfaces of members such as If and 2) are notched. If a link 51 is to be moved to the right by a key bar, the member 2 presents a full depth notch to the key bar and the member if an uncut portion. If a link 5) is to be moved to the left by a key bar, the member If presents a full depth notch to the key bar and the member 21 an uncut portion. If a link 5] is to remain in middle position, both members If and 2] present a half depth notch to the key bar.

The largest number of elements comprised in any Morse signal for which the apparatus shown in Figs. 1 and 2 is adapted is seven, and consequently six combination bars like that shown are provided, the last element in the case of signals having the maximum number of elements being transmitted automatically. Combination bars not required for the elements of a particular signal are set to the space position. For example, for

the letter U the actuation of the key forthis letter causes the link 5 of the first combination bar to be moved to -the left, the link 5 of the second combination bar also to be moved to the left, the link 5 of the third combination bar to be moved to the right and the link of the fourth, fifth and sixth combination bars to be moved to middle position.

Each key bar 5 also engages a trip bar I mounted upon a pair of bellcrank levers 8 and 9, connected together by a link l0. Thus actuation of any key bar moves link If! to the left. Link if! carries a pin I l engaging with the upper arm of a two armed lever 12, the lower arm of which carries a pawl Is. to the left, rotates lever l2 anti-clockwise against tension of a spring 11 and moves pawl l3 to the right. Pawl l3 co-operates with the upper end of a lever M fixed on a shaft l5, and thus when moved to the right rotates shaft l5 clockwise. A lever i6 fixed on shaft I5 is thus moved clockwise against spring 31 and an extension H on lever it is moved from engagement with the extension it? of a lever 19, another extension 2f.) of which engages with an escapement wheel .24 fixed to shaft 22. Lever i9 is fixed to a sleeve 26, freely mounted on shaft 2?. Sleeve carries a cam lever 28 co-operating with a cam 29 on shaft 22, When extension I! is disengaged from extension E3 on lever l9, this lever and with it sleeve 2% and'lever 28 are moved clockwise by a spring 34, bringing lever 23 into engagement with cam 29 and releasing shaft 22 for rotation. Shaft 22 is driven from motor 25 through gear 24 and a friction clutch 23.

As shaft '22 rotates, cam 29 engages cam lever 28 and moves sleeve 25 and with it lever 19 in an anti-clockwise direction and brings projection 20 on lever 59 into engagement with the next tooth on escapement wheel 2 i.

The shaft 22 carries cams Sila and 33b and a frame 2! pivoted on shaft 21 carries rollers engaging these cams under tension springs and 35. When shaft 22 has rotated from initial position, cams 29a and 39b allow springs 35 and 35 to rotate frame clockwise. Frame 3| thus engages the lower surface of pawl l3 and disengages it from the upper end of lever Hi, thereby leaving lever it free to be again moved by spring 21 to bring extension I! of lever l 6 against extension 18 of lever l9 and holding projection 20 on lever E9 in engagement with the second tooth on escapement wheel 2! so arresting shaft 212.

To each link of a combination bar is fixed an extension 38 having a portion 33 cut with corrector teeth 32. The upper edge of frame 3| is formed with a knife edge and when the frame moves clockwise the knife edge engages between the Corrector teeth 33 of all the combination bars, which are thus held in the positions into which they have been moved, the combination bars being thus 1ocked.

If the key that has been depressed is released it rises, thereby permitting trip bar 7 to rise and the associated link if] to be moved to the right under the influence of spring 17 urging lever i2 clockwise. Pawl l3 consequently moves to the left. If the distributor shaft 22 has not at this time completed its rotation, a step 16 on pawl 13 when moved beyond frame 3!, now in its actuated position, engages the vertical face of that frame. Consequently neither the same key, nor any other key can be depressed during the time that frame 31 is held in its upper position.

Thus movement of link it tacts iii.

The extension 38 is provided with rounded end which engages a slot in an interposing member 39. The interposing member 39] corresponding to the link 5 of the sixth combination bar is shown, the interposing members 39a, 39b, 39c, 39d and Ste of the other combination bars are all similar to member 39 but are shown broken away for the sake of clearness. The interposing members are slidably mounted on cam levers 46a 48b, 490, see, llie and 59 only the last mentioned of which is shown in full. A projection 4| on each cam lever engages with a corresponding cam 42 on shaft 22.

In order to make the operation of the apparatus clear the transmission of the letter U will be first described. As Stated above, for this letter the first two links 5a and 5b (not shown) are moved to the left, the next link So (not shown) is moved to the right and the remaining links 541, 5c (not shown) and 5] are moved to middle position.

When shaft 22 moves through the first step a cam 62a thereon engages the projection All on the first cam lever 40a and momentarily lifts this cam lever and the corresponding interposing member 32a. A projection 54a (not shown but similar to NJ) thereon is below the bail member 5, since the interposing member 39a has been moved to the left; Bailmember 25 is pivoted on shaft 2'? and rotates counter clockwise against the action of a spring (not shown). An exten sion 48 on bail member 45 is thus removed from engagement with an escapement member 49 fixed to a sleeve as on the shaft 5i. Shaft bl is continuously driven by the motor 25 through a gear 52 and sleeve 56 is freely rotatable on shaftiil and driven from that shaft through a friction clutch (not-shown); Sleeve 55 carries cams 53 and 5 t. There are two teeth on the escapement member 59 and so sleeve-5Q is allowed to rotate forhalf a revolution, before being arrested. Cam 5d co-operates with a cam lever 55 fixed to a sleeve iifiifreely rotatable on shaft [5 and carrying a second cam lever 51 acted on by a spring 555 which accordingly holds cam lever 55 against cam 54 and cam lever 5? against a cam 63. Cam lever. 55 carries a pin 62 acting on a pair of con- When sleeve iii rotates therefore earn 5 1 causes pin 66 to actuate contacts i! to generatea dot. As cam sleeve 5t approaches its stopping position cam 53 acts on cam lever 55 fixed to shaft l5 and so rotates the shaft Iii clockwise and with it lever 16. Extension It is withdrawn from engagement with lever it and so projection 2t is withdrawn from escapement wheel 2 i. Shaft 22 again rotates.

In moving through a second step, the cam 29 brings projection 21'} back into the path of the teeth on escapement member 2!. The rotation of shaft 22 through this further step causes cam 42b to lift cam lever 49b and interposing member 39?) momentarily, and as this latter has been set for a dot element bail member 45 is once more rotated anti-clockwise, sleeve 55 is once more re-- leased for rotation and a further dot is trans mitte'd.

The cam E3 is so formed that the release of shaft 22 occurs at such a time that the actuation of the bail member 45 will occur at the moment when the escapement member 49 would be striking the extension 48 of the bail member if it had not justbeen moved. Thus the escapement member 49 is permitted (in this case) to move arrested.

Cam 53 then releases shaft .22 for rotation through a, third step, causing cam 420 to lift cam lever Mic and interp-osing member 390 momentarily. The projection Mo on interposing member 390 is below bail member 46 and this bail member is rotated anti-clockwise. An extension 59 on bail member 46 is removed from engagement with an escapement member EB fixed to a sleeve 6| which is frictionally driven by means of a clutch (not shown) from shaft Sleeve 6| carries a cam 63 which acts on cam lever 5'1 and so rotates sleeve 58 and cam lever 56 to cause pin 66 to actuate contacts 61 to transmit a dash. Escapement member 69 has one tooth only so that sleeve 6| executes a full revolution. Just before the completion of the revolution cam 62 acts on cam lever 64 fixed to shaft |5 to rotate that shaft and lever It clockwise and this results in shaft 22 and escapement member 2| being releaser for a fourth step.

If during the fourth step of shaft 22, bail member 56 were again to be rotated anti-clockwise as for some other character, extension 55 would be removed from the path of the tooth on escapement member 333 at the correct instant to allow of the rotation of sleeve 8| continuing uninterruptedly.

The fourth step of shaft 22, in the case considered, causes cam 42d to lift cam lever d and interposing member 39d momentarily. The projection 64d on interposing member 33d accordingly moves bail member 3'! anti-clockwise to remove extension 68 thereof from engagement with an escapement member 39 fixed to a sleeve Ill. Sleeve iii is driven through a friction clutch (not shown) from shaft and accordingly rotates. Escapement member 69 also co-operates with one arm of a two armed lever I3 urged in a counter clockwise direction by a spring 1'5. and when escapement member 69 has rotated through approximately one third of a revolution it will be arrested by the end of the two armed lever 13. In this position the hump on a cam fixed to sleeve It, will engage with a cam projection I2 on lever I6 and this lever will be moved against spring 37 and held in such position that extension ll thereon is clear of extension I8 on lever I9. Lever is is accordingly withdrawn by spring 34 from engagement with escapement member 2| on shaft 22, which accordingly rotates. As the shaft 22 rotates, the next hump on the resetting cam 29 will reset the lever I9 as before, but the lever I5 is not now able to spring up behind the extension it! to hold the lever IS in the path of escapement 2|. Lever I9 therefore moves outwards clear of the path of escapement 2| and shaft 22 continues to rotate. Cam 29 continues to reset lever I?) as each hump passes the cam lever 28 but'witho-ut arresting the escapement 2|, as in each case, after the cam lever 28 has passed the hump on the cam 29, lever I9 is withdrawn again from the path of escapement 2| under the action of spring 34. Shaft 22 therefore, rotates continuously through the remaining steps of the revolution. The cams 32e, 421 and 42g actuate their corresponding interposing members which are all in the space position to move bail member ll in an anti-clockwise direction, but without any effect on the escapement member 69 because it is held by the end of two armed lever 13.

As the hump on the last cam 42g passes its associated cam lever, the hump on a cam I4 fixed to shaft 22 actuates the two armed lever 'I3to release the escapement 69. The escapement 69 completes its half revolution and is arrested by the extension 68 on the bail member 41 which by this time has been moved back into normal position by its spring. Immediately the lever I3 releases escapement 69 the hump on cam moves clear of cam projection 12 on cam lever I6 thereby permitting the extension I! thereon to be moved by spring 31 against the extension l8 on lever l9. Thus when lever I9 is reset by the last hump on the resetting cam 29, lever I9 is held in the path of escapement member 2| by extension I! on lever l6. Shaft 22 thus comes to rest at the end of its revolution.

During the last step of shaft 22, cams 30a and 39b act on the rollers carried by frame 3| to rotate frame 3| in an anti-clockwise direction thereby releasing the combination bars andalso permitting pawl I3 to be lowered onto an abutment I8, so that the frame 3| is dise gaged from step 16 and the pawl I3 re-engages with lever I4. If, during transmission of the signal above described, pressure had been applied to another key, immediately the combination bars are unlocked by the action of cams 30a and 3%, the second key will go down, thereby resetting the combination bars and the trip bar. The pawl l3, acting on the lever l4, releases the lever l9 so permitting the shaft 22 to make the first step of the next revolution. This action is so timed that the shaft 22 can move through its normal stopping position without being arrested. It is to be noted that the combination bars are left in the positions into which they were set, but when unlocked are free to be reset by another key bar.

The time taken for an uninterrupted half revolution of sleeve 10 is the duration of two time units during which contacts 67 remain open and this, added to the space of one time unit duration transmitted during the rotation of sleeve 50 or of sleeve 6| completes the normal letter space of three units. To the extent that sleeve I0 is arrested before it completes a half revolution the letter space is prolonged until shaft 22 has completed a revolution. The speed of rotation of shaft 22, however, when rotating uninterruptedly is such that the prolongation of the letter space beyond three units duration is only very slight and cannot exceed, even in the case of the shortest signals, something less than two units. There is no prolongation at all in the case of signals having the maximum number of elements. To take care of a letter space completing such signals a seventh cam 429 is provided on shaft 22 which acts on a seventh interposing member 43. This latter member is not controlled by a combination bar but is fixed with its nose underneath bail member 41. At the end of the signal elements transmitted under control of cams 42a 42 and interposing members 390. 39f acting on bail member 45 and/or bail member 66, interposing member 43 lifts bail member 41 and so allows sleeve I0 to rotate. This rotation of sleeve I0 is uninterrupted for half a revolution, cam I4 removing two armed lever I3 from engagement with escapement member 69 at the correct instant to allow of sleeve 10 not being arrested thereby.

The maximum speed of transmission with the transmitter of Figs. 1 and 2 is attained when a key is actuated and the finger of the operator passes immediately to another key and actuates that as soon as possible. As previousl described the keyboard is locked in such manner that one actuation of a key results in one transmission only of the character represented by the key, however long the key is kept actuated, and after actuation of one key for one signal, transmission of a further signal is prevented until either (a) thefirst transmission is completed or (b) the actuated key is released, whichever happens last. It is also the case with the arrangement shown in Figs. 1 and 2 that not only is transmission of a further signal prevented but also operative actuation of a key is prevented whilst the combination bars are locked in position during the transmission of a signal. Certain keys can, however, be partially depressed whilst the combination bars are locked, i. e. such keys as have keybars that are presented with either a full or a half way notch in each combination bar or with a full notch in some bars and a half notch in others. The operator may therefore receive the impression that a key has been actuated when in fact it has not and no transmission of the. signal has taken place. In order to overcome this slight difficulty additional combination bars are arranged, cut in such a manner that, with the six combination bars above described, they prevent depression of any key. even half way, when they are locked during the transmission of a signal. The additional combination bars do not act on the transmitting mechanism and merely co-operate with the frame 3| for locking purposes. The preferred manner in which the notches in these additional combination bars are arranged in relation to the key bars for the purpose above stated will be clear from the following;

For co-operation with the transmitting mechanism it is immaterial which positions of a combination bar represent which elements. It is only necessary to arrange that the frames 45, it, 41 corresponding to the three positions release the appropriate cam sleeves. An combinationbar moved into one extreme position will prevent any movement of all key bars to which it presents the condition for the opposite element, but will not prevent the movement of key bars to which it presents the condition for the same element or for the element represented by the middle position. If the middle position or each link represents a space element as in the embodiment described, then the characters can be arranged in groups, those in each group containing the same number of elements, such that for any character in any one group the six combination bars are set in. positions that prevent an actuation of a key in the same group. fore to arrange additional combination (bars cut the same for the keybars of the characters in any one group but differently for characters in different groups so that the setting of thes additional combination. bars by a key in an group shall prevent the actuation of a key in any of the other groups. There are six such groups and thus the minimum number of such additional combination bars is three, out so that they are set in a different combination of dots and dashesfor each of the six groups of characters.

Fig. 4 shows means by which the keys for letter E and the word space are disassociated from the combination bars and from the trip bar and instead actuate an independent mechanism for the purpose previously described. Fig. 4 also shows the manner in which the latch lever I2, pawl I3 and frame 3i of Fig. 2 are modified to accommodate the separate mechanism. .for transmitting the two signals above mentioned. The latch lever I2 of Fig. 4 is divided into two parts Ila and I2?) Iboth fixed to a rod 5%. The part I20. co-operates with the pin II, Fig. 2, whilst part I2a has mounted thereon a pawl Ba.

It only remains there- An extension on the underside of the keybar corresponding to the letter E abuts against one end of a two armed lever I00 and when the key i actuated this lever I00 is rotated in an anticlockwise direction, raising a latch is! carried thereon. This latch engages a detent lever I92 and raises it clear of a stop arm Hi3 fixed to a sleeve I04 frictionally driven from the shaft 5i. Sleeve Ill i is therefore permitted to rotate until a stop cam H9 carried thereon is arrested by a cam lever I28.

Cam lever I253 co-operates with a cam I 2I on shaft 22 and if this last mentioned shaft has been rotated. from its initial position cam I2I allows cam lever I20 to be moved into the path of stop arm H9. The key for letter E can thus be actuated even if the machine is engaged in transmitting signals and the keys that co-operate with the combination bars and trip bar are locked. The short movement of sleeve I04 between its release by movement of detent lever I62 and its arrest by cam lever I29 is sulficient to cause cam I05! 0n sleeve IM to rotate lever I08 in a counter clockwise direction. A tooth On the end of lever I08 presses against the end of latch IOI so disengaging that latch from detent lever I92 and allowing the latter to be returned into the path of stop arm I03. It, now the E key is released and lever H10 and latch IIlI return to their initial positions, the tooth on the end of lever IIlB engages tooth Ill! and holds latch IIJI and lever Ills against a second actuation. Lever I08 is fixed to rod I39 to which also is fixed a lever I28, so that when lever I68 is rotated anti-clockwise lever I28 rotates with it and engages latch I24 to prevent actuation of the word space key until transmission of letter E is completed.

At the same time a cam I It on sleeve Ill-l moves a cam lever I II in clockwise direction. Cam lever I I I is fixed to a second cam lever I I2 having an extension 5 I5 and this extension is thus raised to the rear of a latch Ilia.

When the mechanism shown in Fig. 4 is added to the keyboard transmitter of Figs. 1 and 2, the latch is shown in the latter is modified into the shape shown at Eda in Fig. l and no longer co-operates directly with the frame 3|. Instead, the frame SI carries a pin I22 which passes underneath the extension II5 of cam levers I II and I i2. Thus when extension i I5 is raised either by the movement of frame 3i when shaft 22 moves from normal position, or by the action of cam I EU on cam lever I I I, latch I3a is prevented from moving into engagement with lever I4.

Thus the trip bar is locked until the transmission of the letter E is completed. The movement of sleeve E84 out of normal position stores the letter E until the transmission of any other signal is completed. When this latter transmission is completed and shaft 22 returns to normal position cam lever I29 is moved by cam I2I out of engagement with stop arm I I9 and sleeve I64 continues its rotation. If the shaft 22 were in its normal position when the key for letter E was depressed, the sleeve Hi l would not be arrested by lever I2il but would continue its rotation. During the further rotation of sleeve I04 a cam H6 thereon. acts on a cam lever II i to actuate contacts M8 to generate a dot and the letter space following it thus transmitting the letter E. Contacts H3 are arranged in parallel with contacts 6'? of Fig. 2. When sleeve I04 reaches its initial position it is arrested by re-engagement of lever I92 with the stop arm H13. Cam I05) allows cam lever N28 to be moved clockwise clear ll of latch IElI and with it lever I28 clear of latch I24 and cam Ill! allows cam lever III to move anti-clockwise and remove extension H from the path of latch I3a. Another signal can then be transmitted.

The key bar for the word space is also arranged so that, when it is depressed, it does not actuate the combination bars or the trip bar. Instead, it acts to move anti-clockwise a two armed lever I23, similar to lever Hi9 to which is pivoted a latch I24 similar to latch I ill. Latch I24 raises a detent lever I 25 out of engagement with stop arm I25 on a sleeve H4 driven through a friction clutch from shaft 5i. Sleeve I I4 commences to rotate and a cam I27 moves cam lever I28 to press against the end of latch I24 and disengage it from detent lever I 25 and so allows that detent lever to be returned into the path of stop arm I26. Lever I (38 moves with lever I28 and engages the tooth on latch IEII to prevent actuation of the key for letter E. If the word space key is released and latch I24 returns to initial position the hook on the end of lever I28 engages the tooth on latch I24 to prevent a second actuation of the space key until the sleeve I I4 reaches normal position. If shaft 22 is out of normal position sleeve I I4 is arrested after a small movement by cam lever I20 engaging with a stop arm I29 on sleeve IM. Cam H3 on sleeve H4 acts on cam lever M2 to raise extension H5 thereof behind latch 3a and prevents its movement. Sleeve I M does not carry a cam operating on contacts as its function is solely to introduce a time delay corresponding to the space between Words. Sleeve I I4 may be arranged to make either a half revolution or a full revolution at each release according to the time interval required between words. I

It is clear that the key for the letter T could, if desired, be disassociated from the combination bars and caused to release a separate cam sleeve for the transmission of that letter in a manner similar to that shown in Fig. 2 for the key for letter E and the word space key and would be interlocked with the mechanism shown so as to store the letter T but prevent transmission of any other signal until transmission of the T signal was completed.

The mechanism above described may be combined with a recorder for recording received signals upon a tape in the manner shown in Fig. 1. There is shown in that figure a receiving magnet 80 the armature 8! of which is withdrawn from the magnet, when not attracted thereto by energisation of the magnet, by a spring 94. The armature 8! is provided with an extension 82, which, when the armature is attracted produces marks on a tape 89 by striking it against an inked roller 83. The inked roller is mounted on shaft 84 driven from motor 25 through gearing 1. A keyboard operated Morse code transmitter comprising a plurality of keys each representing a character, means common to all keys and selectively actuated by each key for analyzing into elements the Morse signal corresponding to the key character means common to all keys for causing transmission of said elements in sequence in accordance with the operations of said selectively actuated means, and means for returning the transmitter to transmitting position after the final element of said signal has been sent.

2. A transmitter as set forth in claim 1 including a key bar associated with each key, in which the means for analyzing said signal comprises combination bars and means controlled by the key bars, selectively placing the combination bars in position.

3. A keyboard operated Morse code transmitter comprising a plurality of keys each representing a character, a plurality of combination bars and control means actuated by the operation of each key for selectively setting all of the combination bars to give positions corresponding to the elements of the Morse code signal representative of said key and causing said elements to be transmitted in correct sequence.

4. A transmitter as set forth in claim 3, in which the number of combination bars is one less than the maximum number of elements in any signal, means for selectively setting said bars by the operation of keys representative of signals having difierent numbers of signal elements and means for setting each bar not required for the elements of a signal in a position corresponding to the last element of a signal.

5. A transmitter as set forth in claim 3, in which the number of combination bars is one less than the maximum number of elements in any signal, said control means being efiective for setting said bars by the operation of keys representative of signals having only the maximum number of signal elements, means responsive to the actuation of each of the latter keys for causing the transmission of the last signal element independently of the combination bars, said control means being effective for selectively setting said bars by keys representative of signals having less than the maximum number of elements, and responsive to the actuation of each of the latter keys for setting in a position corresponding to the last element of a signal each bar not required for the elements of a signal.

6. A keyboard operated Morse code transmitter comprising a plurality of keys each representing a character, means selectively actuated by a key for analyzing into elements the Morse signal corresponding to the key character means com- 85, and is inked by means of an inking roller 91 which dips into a bath of ink and is mounted on a lever 92 urged by a spring 93 lightly against roller 83. The tape 89 is drawn from a roll 9.! by means of feed rollers 88 and 5D. Roller 88 is mounted on shaft 8? driven from the motor through gears 86.

A send-receive switch (not shown) is provided to connect either the transmitter or the recorder to the transmission medium and the lever that operates this switch may also move shaft 81 to remove roll 83 from pressure against feed roll when the switch is in send position and so stop the feed of the tape. 4

What is claimed is:

mon to all keys for causing transmission of said elements in sequence by and in accordance with the operations of said selectively actuated means, said analyzin means including a plurality of combination bars and means controlled by actuation of a key for setting said bars into selected position corresponding to the key character, three separate means for transmitting the three different signal elements, means controlled by the setting of a combination bar for causing actuation of the corresponding transmitting means,

and distributor means for controlling the sequence of actuation of the different transmitting means. i

7. A keyboard operated Morse code transmitter comprising three separate and structurally distinct and independent selectively operative means for transmitting the three different elements of a Morse code signal, and key actuated means for determining the proper sequence in the operation of said selectively operative means.

8. A keyboard operated Morse code transmitter comprising three separate selectively operative means for transmitting the three different elements of a Morse code signal, key actuated means for determining the proper sequence in the operation of said selectively operative means, the separate transmitting means each comprising a separately driven cam, key controlled selectively operative means determining the operative movement of each of said cams, and means actuated by its associated cam for generating the respective signal element.

9. A keyboard operated Morse code transmitter comprising a plurality of keys each representing a character, means operated by actuation of a key for analyzing into elements the Morse signal corresponding to the key character and causing leasing the shaft for rotation, means operated by the shaft during rotation for transmitting the signal elements in correct sequence and means for controlling the shaft rotation to provide one step of rotation for each signal element to be transmitted.

10. A transmitter as set forth in claim 9, comprising means actuated by the transmission of a space element of a signal for returning the distributor shaft to starting position.

11. A transmitter as set forth in claim 9, comprising means for locking the keys against actuation when the distributor shaft is out of starting position.

12. A keyboard operated Morse code transmitter comprising a keyboard, means actuated by the keyboard for transmitting code signals of different lengths, means for locking the keyboard against operation during the transmission of signals, and short signal means operative after the transmission of a signal of less than maximum length for unlocking the keyboard.

13. A keyboard operated Morse code transmitter comprising a plurality of keys each representing a character, a plurality of combination bars and means actuated by the operation of each a key for selectively setting the combination bars in positions corresponding to the elements of the Morse code signal representative of said key and causing said elements to be transmitted in correct sequence, and separate means for transmitting a short signal, said latter mean being independent of the combination bars and including an operating key representing said signal.

14. A transmitter as set forth in claim 13, comprising means operative upon actuation of the latter key during transmission of a signal controlled by the combination bars for storing said short signal upon the actuation of said latter key and causing the transmission of said short signal immediately after the completion of the signal controlled by the combination bars.

15. A transmitter as set forth in claim 13, in which said separate means comprises means ef- Ill fective upon actuation of an operating key for preventing the action of any key on the combination bars until said short signal has been transmitted.

16. A transmitter as set forth in claim 13, comprising a plurality of keys each representing a short signal, a plurality of cams, means for rotating said cams, means for releasing each cam forrotation actuated by operation of a key, and means effective upon actuation of any short signal key for preventing actuation of any other of said keys.

1'7. A keyboard operated Morse code transmitter comprising a plurality of keys each representing a character, a plurality of combination bars and means selectively actuated by the operation of each key for setting the combination bars in positions corresponding to the elements of the Morse code signal representative of said key and causing said elements to be transmitted in correct sequence, each combination bar comprising a pair of code bars arranged side by side, means whereby selective movement may be imparted to said code bars by a key bar, or no movement will be imparted to either code bar, and link means connecting adjacent ends of a pair of code bars so arranged that, when one code bar is moved in one direction the other code bar is moved in the opposite direction, whereby the link may be located one of three positions according to the order of the code elements represented by the actuating key bar.

18. A transmitter as set forth in claim 3, in which each combination bar comprises a pair of code bars, key actuated means for shifting a code bar vertically and link means connecting registering ends of each pair of code bars for moving said code bars in opposite directions, additional combination bars movable only into extreme upper and lower positions, and means including said additional combination bars effective upon actuation of a key for holding all other keys against actuation.

19. A keyboard operated Morse code transmitter comprising a plurality of keys, key bars operated thereby, interposing members having three set positions, means including three independently rotatable cam sleeves for transmitting three different elements of a code signal, bail members each associated with a cam sleeve, a distributor shaft, means operated by actuation of a key bar for setting the interposing members in conformity with the elements of a code signal, means operable upon actuation of a key bar for releasing said distributor shaft for rotation through one step, means on said distributor shaft operated during each step of the rotation for actuating a separate interposing member to move one of said bail members, means operated by said movement of a bail member for releasing the associated cam sleeve for rotation, means actuated upon the completion of rotation by either of two of the cam sleeves for releasing the distributor shaft for movement through a further step, means operated by the third cam sleeve for releasing the distributor shaft for rotation into its original position, and shaft rotating means.

ALFRED EDWARD THOMPSON. REGINALD DENNIS SALMON, 

